Instrument procedures (e.g., instrument approach procedures or instrument departure procedures) are used to provide specific detailed instructions for the operation of aircraft in the airport terminal area, and allows air traffic control to reduce radio frequency congestion by communicating only the name of the procedure to be flown, rather than having to provide the verbose instructions otherwise required. For example, instrument approach procedures allow a pilot to reliably land an aircraft in situations of reduced visibility or inclement weather by using instruments onboard the aircraft or on the ground, such as radios or other communication systems, navigation systems, localizers, glidescopes, and the like. Published aeronautical charts, such as, for example, Instrument Approach Procedure (IAP) charts, Standard Terminal Arrival (STAR) charts, or Terminal Arrival Area (TAA) charts Standard Instrument Departure (SID) routes, Departure Procedures (DP), terminal procedures, approach plates, and the like, that depict and describe the instrument procedures for various airports, runways, or other landing and/or departure locations are provided by a governmental or regulatory organization, such as, for example, the Federal Aviation Administration in the United States. These charts graphically illustrate and describe the specific procedures (e.g., minimum descent altitudes, minimum runway visual range, final course or heading, relevant radio frequencies, missed approach procedures) to be followed or otherwise utilized by a pilot for a particular approach or departure. A pilot maintains copies of these printed charts for the various possible airports that the pilot may encounter during operation of the aircraft. For example, for worldwide operation, there are as many as 17,000 charts, and each airport may include multiple runways with multiple possible approaches and departures.
Typically, in advance of the actual approach or departure, the pilot identifies the airport and reviews the charts for the one or more approaches (or departures) for that airport. Once the pilot determines the approach (or departure) that the pilot intends to fly, the pilot and crew (e.g., the co-pilot) review features of the instrument procedure such that there is sufficient understanding and agreement on how the procedure should be executed based on the chart. These printed charts contain a significant amount of information making it difficult to display them in their entirety electronically onboard the aircraft. For example, in current electronic cockpit displays, the resolution and physical size of the electronic display limits or prevents the instrument procedure charts to he reproduced or replicated electronically. Furthermore, most of the display area on the electronic display is already utilized or reserved for other processes (e.g., navigational maps, profile views, synthetic vision displays, flight management windows, and the like) and presenting the instrument procedure chart risks interfering with or obfuscating these other processes.
Instrument approach plates include a vertical profile for a desired approach that consists of a series of navigational segments with constraining altitudes (e.g., minimum descent altitudes) and additional graphical and textual information corresponding to the various stages of the approach and/or departure. Often, the published vertical profiles are unscaled in both the horizontal and vertical dimensions. However, placing aircraft symbology and/or the terrain on a vertical profile that lacks a fixed vertical scale is misleading to the pilot. In addition, the navigational segments vary greatly in size, some being only a half mile or less while others may be ten or more miles long. Therefore, given the limited display area allocated to the vertical profile, attempting to display the navigational segments with a fixed scale causes some smaller navigational segments to be imperceptibly small and creates difficulty in displaying the necessary text between waypoints for the navigational segment, while some larger navigational segments require an unwieldy amount of the display area.